Improvement in lifting-jacks



UNITED STATE$ PATENT @FFICE.

IMPROVEMENT IN LIFTlNG-JACKS.

Specification forming part of Letters Patent No. 135,551, dated February4, 1873.

-ment and combination of parts, which .will be more fully set forth hereafter.

Figure 1 represents a side elevation of my jack. Fig. 2 is a plan view of the same, the

lit'tingplate being removed. (t represents a cast-iron hollow standard, upon the top of which is ashort standard, b, in which the. lever c is pivoted. In the side of the top of the standard is a slot, (1, in which the friction-dog c is held by the projections upon its lower end and by passing over the litting-rod g, as shown in Fig. 2. By this arrangement the dog is always kept in the desired position, ready for use at any minute. Slipped over the lifting-rod is a friction-plate, h, which is operated by the bifurcated end of the lever c. By working the lever up and down this plate is made to bite by frictional contact the side of the rod, so as to alternate 1y raise the rod, and then descend by its own gravity for another hold. As soon as the upward motion of the rod ceases the dog catches the rod and prevents it from descending, while the triction-plate h slides down to again take hold. Pivoted to the top of the standard is a swinging lever, it, which can be swung around so as to catch under the edge of the dog, and, by preventing it from falling forward on the rod, keeps it from catching hold.

\Vhile the dog is thus held, by letting the plate It rest upon its top, the rod is released and falls at once back into the standard.

Having thus described my invention, what Iclaim as new, and desire to secure by Letters Patent, is-' 1. The dog 0 held in position by lifting-rod and slotted standard, substantially as set forth.

2. The pivoted lever c for holding the dog from contact with the rod, substantially as shown.

3. The dog 6 held as described, the lifting plate h, rod g, and lever 0, when arranged to operate as specified.

4. The standard a, lever 0, slot (1, dog 6, rod 9, lifting-plate h, and lever 2', when all are combined to form a lifting-jack, substantially as shown and described.

In testimony that I claim the foregoing as my invention I hereunto affix my signature this 26th day of December, 1872.

JACOB H. HINTON.

'itnesses:

S. R. BONEWITZ, J. H. CARR. 

